package com.tianqu.tms.core.util;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.nio.MappedByteBuffer;
import java.nio.channels.FileChannel;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class MD5Util {
	 protected static char hexDigits[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9','a', 'b', 'c', 'd', 'e', 'f' };
	 protected static MessageDigest messagedigest = null;
	 static{
	     try{
	      messagedigest = MessageDigest.getInstance("MD5");
	     }catch(NoSuchAlgorithmException nsaex){
	      nsaex.printStackTrace();
	     }
	  }
	 public static String getFileMD5String(File file) throws IOException {
	     FileInputStream in = new FileInputStream(file);
	     FileChannel ch = in.getChannel();
	     MappedByteBuffer byteBuffer = ch.map(FileChannel.MapMode.READ_ONLY, 0, file.length());
	     messagedigest.update(byteBuffer);
	     in.close();
	     ch.close();
	     
	     return bufferToHex(messagedigest.digest());
	  }

	  public static String getMD5String(String s) {
	     return getMD5String(s.getBytes());
	  }

	  public static String getMD5String(byte[] bytes) {
	     messagedigest.update(bytes);
	     return bufferToHex(messagedigest.digest());
	  }

	  private static String bufferToHex(byte bytes[]) {
	     return bufferToHex(bytes, 0, bytes.length);
	  }

	  private static String bufferToHex(byte bytes[], int m, int n) {
	     StringBuffer stringbuffer = new StringBuffer(2 * n);
	     int k = m + n;
	     for (int l = m; l < k; l++) {
	      appendHexPair(bytes[l], stringbuffer);
	     }
	     return stringbuffer.toString();
	  }

	private static void appendHexPair(byte bt, StringBuffer stringbuffer) {
	     char c0 = hexDigits[(bt & 0xf0) >> 4];
	     char c1 = hexDigits[bt & 0xf];
	     stringbuffer.append(c0);
	     stringbuffer.append(c1);
	  }

	  public static boolean checkPassword(String password, String md5PwdStr) {
	     String s = getMD5String(password);
	     return s.equals(md5PwdStr);
	  }
}
